1 If I HAD SEEN… (see) the film in the cinema, I wouldn't have watched it on TV again.
2 If the parents bought the cat, their children … WOULD BE (be) very happy.
3 Metal … (expand) if you heat it.
4 He … (read) my e-mail if he'd been online yesterday evening.
5 They'd have been able to return the bottle if they … (read) the labels.